1. Field of the Invention
The present invention relates to a method for preventing the formation of a popcorn chloroprene polymer.
1. Description of the Prior Art
Chloroprene monomer tends to undergo popcorn polymerization (otherwise known as .omega.-polymerization) whereby opaque granular solids are formed during storage of the monomer, or during a process step, such as distillation or the production of polymers from the monomer. Once the popcorn polymer forms, it tends to act unfavorably as a nucleating site for the absorption and consequent consumption of chloroprene monomer. Once the formation of the popcorn polymer has started, it continues to grow at a very rapid rate and detrimentally acts to clog the process equipment. Because the popcorn polymer which forms is not soluble in solvents, its formation must be prevented.
Heretofore, in order to inhibit .alpha.- and .mu.-polymerization during the storage of chloroprene monomer or during the production of chloroprene polymers, it has been known to add a stabilizer such as phenothiazine and/or tertiary butylcatechol to the monomer. However, these inhibitors are ineffective in preventing .omega.-polymerization (popcorn polymerization) and .beta.-polymerization of chloroprene monomer.
A need therefore exists for an inhibitor which effectively prevents .omega.-polymerization of chloroprene monomer.